Treatment-resistant Chronic Constipation: Sign of an Underlying Motility Disorder

Most gastroenterologists have encountered patients who complain of chronic constipation. Colonoscopy shows no anatomical abnormalities. Nonetheless, conservative treatment with laxatives and bulking agents brings only temporary, minor relief. After several failed treatment attempts, the patient is distressed, uncomfortable and anxious; the gastroenterologist is frustrated. Deborah Bethards, MD, a gastroenterologist at Penn State Health Milton S. Hershey Medical Center’s Neurogastroenterology and Motility Clinic explains, “Failure of conservative treatment to resolve constipation should be a red flag. With no other detectable abnormality, the possibility of a chronic pelvic floor disorder that primarily affects women—known as dyssynergic defecation—should be considered.”

With this disorder, the rectosigmoid area does not function properly so that during attempted defecation, paradoxical anal contraction occurs, and pelvic floor muscles fail to relax. The result is that stool is retained in the rectum. If left untreated, complications such as fecal impaction, rectocele, megacolon, and fecal incontinence may occur.

Diagnosis of dyssynergic defecation is based on an in-depth patient interview, along with digital rectal exam (DRE) and anorectal manometry. Bethards notes, “It’s important to ask the patient pointed questions about their bowel habits as they often do not volunteer sometimes embarrassing details. Patients may report that when trying to defecate, they sit for long periods of time, strain, and use different positions, as well as digital maneuvers. Even with defecation, the patient senses incomplete evacuation. DRE may show diminished sphincter tone and inability to relax the sphincter when asked to strain.”

While traditional anorectal manometry is useful, new higher resolution technology yields more precise, readily interpretable measures. Milton S. Hershey Medical Center’s Neurogastroenterology and Motility Clinic is one of only eleven state-of-the-art facilities in the United States that serves as a motility disorder teaching center for GI fellows. Bethards explains, “By using high-resolution anorectal manometry available in our center, we can detect different causes of dyssynergic defecation such as absence of reflexive anal sphincter relaxation in response to increased pressure in the rectum [via balloon inflation] that may represent a congenital problem, or failure to relax the anal sphincter and pelvic floor when simulating defecation that represents an acquired behavioral problem. Patients with pelvic floor dysfunction are unable to expel the balloon and less likely to sense its inflation.”

Additional investigations may be needed to detect motility problems involving other areas of the gut, such as slow transit constipation. “Patients may also have complications like rectocele, severe hemorrhoids, or urinary incontinence. In our motility clinic, we interact with colorectal surgeons, urologists, radiologists, and gynecologists,” says Bethards.

Dyssynergic defecation often significantly improves with biofeedback training. Bethards notes, “Patients receive between six and eight biofeedback sessions that retrain the involved pelvic floor and sphincter muscles. Patients should be instructed to continue the technique at home but still need bi-annual ‘refresher sessions’ to maintain healthy bowel movement patterns.”